Background: When conducting literature searches for systematic reviews one bibliographic database, MEDLINE, is almost always included. MEDLINE content can be searched via numerous different search interfaces, the majority of which are provided by fee-based subscription services (e.g. OvidSP), although it can be accessed for free using PubMed. Many information specialists would choose to search using sophisticated interfaces (usually fee-based) that enable the design of complex search strategies. PubMed has more limited search capabilities, for example proximity searching is not possible. However, 2% of PubMed records are not found in MEDLINE, including newly published and ahead-of-print articles.
Objectives: To investigate whether conducting a supplementary search of PubMed in addition to the main MEDLINE (OvidSP) search is worthwhile. We will explore whether an extra PubMed search can be conducted quickly and retrieve unique studies that are included in the review.
Methods: Searches of PubMed will be conducted after MEDLINE and MEDLINE In-Process (OvidSP) searches have been completed. Due to different levels of functionality in search interface, exact translation of the MEDLINE strategy may not be possible; in this instance the objective is not to duplicate searches, rather to supplement them. Search strategies will be simplified, using phrase searching predominantly. The searches will be limited to records not in MEDLINE, using the following limit:
(pubstatusaheadofprint OR publisher[sb] OR pubmednotmedline[sb])
Results: We will consider whether additional searching time and screening burden from supplementary PubMed searches generates unique included references.
Conclusions: Ensuring that PubMed searches are as current as possible can determine the timeliness of the final review. It may also be worth establishing search alerts in PubMed until final publication.